\section{Introduction}



    Investigation of star forming-regions containing molecular cores that of early evolutionary stages may significantly refine our understanding of initial conditions of star formation.
    However, previous samples were mainly selected from observations at optical and infrared bands, therefore, the studies often focused on locations with star forming activity while pre-stellar cores are less studied.
    For these reasons, new samples of pre-stellar cores selected from bands of longer wavelength are of urgent necessity.
    Fortunately, satellite \emph{Planck}, working at mm/sub-mm bands, systematically provided wealth of galactic cold dust cores. The Cold Core Catalogue of \Planck Objects (C3PO) of 10,783 cold cores, and its sub-catalogue, \Planck Early Release Cold Cores Catalog (ECC), containing 915 most reliable detections have been released (\citealt{2011A&A...536A..22P}). The detailed study towards dust component of each Planck core done by \cite{2011A&A...536A..22P} indicates that the cores in C3PO are of column density $N_ {\rm H_2} \sim 0.1 \rm \ to \ 1.6 \times 10^{22} \rm cm^{-2}$ and dust temperatures between 10 and 15K (\citealt{2011A&A...536A..22P}), deduced from the fluxes in the three high-frequency bands (353, 545, 857 GHz) and the 3000 GHz of IRAS band (\citealt{2011A&A...536A..23P}).

    Besides the detailed study done by \cite{2011A&A...536A..22P} towards dust components, follow-up study of the molecular lines can also refine our understanding of \Planck Cold Cores. Recent study of 674 ECC sources with observation of \coaa \cobb and \cocc as single points were made (\citealt{wu2012gas}) and  the physical conditions, such as kinetic temperature ($T_k$), column density(\nhyd), and velocity dispersion($\sigma$) etc. In this paper, we report a mapping study of \numsou sources in the ECC that have been made single point study by \citep{wu2012gas}. Among the \numsou sources, \numsoutmc are in Taurus Molecular Cloud (TMC), \numsoupmc are in Perseus Molecular Cloud (PMC) and \numsoucmc are in California Molecular Cloud (CMC).  Transitions with $J=1-0$ of CO isotopes, \coa, \cob and  \coc were employed as probes.

    TMC is a typical site of low-mass star formation. As the closest Giant Molecular Cloud (GMC) to us (\citealt{1987ApJ...322..706D}), it contains favorable samples when resolution is limited.
    Towards 90 small visual opaques in TMC and Ophiuchus, \cobb and \cocc observations were made.
    A number of cores with sizes $0.1\sim0.3 \ \rm pc$, masses $4\sim30\ \rm M_\odot$, \texc $\sim$ 10 K were revealed (\citealt{1983ApJ...264..517M}, \citealt{1983ApJ...266..309M}).
    Subsonic turbulence (\citealt{1983ApJ...270..105M}), CO outflow (\citealt{1988ApJ...324..907M}) and morphology of cores (\citealt{1991ApJ...376..561M}) were also investigated in these cores. When molecular outflows were found in high mass star forming regions but could not be resolved (\citealt{1976ApJ...209L.137Z}), L1551 was detected as outflow with red-lobe and blue-lobe separated well (\citealt{1980ApJ...239L..17S}). Among the nearly 400 molecular outflows found before February 2003, 11\%  (outflow sequence number 24$\sim$67 in the reference) were in Taurus (\citealt{2004A&A...426..503W}). Excellent examples of infall motions such as T Tau binary system (\citealt{1994ApJ...425L..45V}) and L 1544 (\citealt{1998ApJ...504..900T}) were also found in TMC. Disk were identified around young stars like HL Tau (\citealt{1991ApJ...382L..31S}) and DM Tau as well (\citealt{1995ApJ...453..384S}). Thus, TMC contains class 0-III sources. They are with evolutional characteristics of star forming phases and are the basic for theoretical models (\citealt{shu1987star}). Also, as almost not affected by external shocks or ultraviolet radiation (\citealt{1995ApJ...445L.161M}), TMC is suitable for studying original physical conditions of pre-stellar cores as well as spontaneous star formation (\citealt{1995ApJ...445L.161M}). For the same reason, TMC may even favorable for studying the formation of molecular clouds from diffuse ISM or atomic clouds.

    Besides TMC, PMC is also a well-known star forming region, in which prototype stars of intermediate masses were identified (\citealt{2010A&A...512A..67L}), which is considered between the low-mass star formation in Taurus and massive star formation in Orion (\citealt{2010ApJ...711..655J}). Combining sub-millimeter and mid-infrared data, 49 deeply embedded young stellar objects (YSO) were identified in PMC (\citealt{2007ApJ...656..293J}). In millimeter band, the whole Perseus was firstly surveyed in CO by \citep{1979ApJ...233..163S}, after which many other CO surveys have been made (\citealt{1999ApJ...525..318P}, \citealt{2005A&A...440..151H}). PMC has a distance of 235$\pm$18 pc to us (\citealt{2010A&A...512A..67L}).

    The California Molecular Cloud (CMC) had not attracted enough attention until the observation and analyze made by (\citealt{2009ApJ...703...52L}), in which the distance of CMC was derived as 450 $\pm$ 23 pc, and combining the spatial extension of over 80 pc, the mass was derived as $\approx 10^5 M_\odot$. The CMC is considered similar to Orion Molecular Cloud in distance, mass and morphology, but with lower star forming activity (\citealt{2009ApJ...703...52L}, \citealt{2010A&A...512A..67L}). A recent mapping survey of CMC has been done by \citep{2013ApJ...764..133H}, which provides a catalog of 60 compact sources at 70 $\mu$m, using \emph{Herschel} PACS and SPIRE as well 18 cold compact sources using Bolocam 1.1 mm camera.  As CMC reveals relatively immature characteristics, it is an ideal sample for studying early evolutionary stages of cold cores in such a huge and quiescent GMC. Besides LLA study and the study by \citep{2013ApJ...764..133H}, further investigation in mm band with higher resolution is also needed to reveal the physical properties of cold cores in CMC.

    In next section, observation is introduced. Results are presented in  Section \ref{Sec. Results} and discussions are in Section \ref{Sec. Discussion}. Section \ref{Sec. Summary} is a summary.
